Commit 67e8e0b9 authored by Graham Leggett's avatar Graham Leggett
Browse files

mod_proxy_balancer,mod_slotmem_shm: Rework SHM reuse/deletion to not 

depend on the number of restarts (non-Unix systems) and preserve shared
names as much as possible on configuration changes for SHMs and persisted
files.  PR 62044.
trunk patch: http://svn.apache.org/r1822509
             http://svn.apache.org/r1822511
             http://svn.apache.org/r1823412
             http://svn.apache.org/r1823415
             http://svn.apache.org/r1823416
             http://svn.apache.org/r1823564
             http://svn.apache.org/r1823572
             http://svn.apache.org/r1823575
2.4.x patch: trunk works (modulo CHANGES)
             (or http://home.apache.org/~ylavic/patches/httpd-2.4.x-PR62044-slotmems_reuse.patch)
+1: ylavic, jim, minfrin


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/2.4.x@1824180 13f79535-47bb-0310-9956-ffa450edef68
parent 19d537f3

CHANGES

+6 −1
Original line number Diff line number Diff line 
                                                         -*- coding: utf-8 -*-

Changes with Apache 2.4.30



  *) mod_proxy_balancer,mod_slotmem_shm: Rework SHM reuse/deletion to not

     depend on the number of restarts (non-Unix systems) and preserve shared

     names as much as possible on configuration changes for SHMs and persisted

     files.  PR 62044.  [Yann Ylavic, Jim Jagielski]



  *) mod_http2: obsolete code removed, no more events on beam pool destruction,

     discourage content encoders on http2-status response (where they do not work).

     [Stefan Eissing]

modules/proxy/mod_proxy_balancer.c

+117 −10
Original line number Diff line number Diff line
@@ -22,6 +22,7 @@ 
#include "apr_version.h"

#include "ap_hooks.h"

#include "apr_date.h"

#include "apr_escape.h"

#include "mod_watchdog.h"



static const char *balancer_mutex_type = "proxy-balancer-shm";
@@ -730,6 +731,115 @@ static apr_status_t lock_remove(void *data) 
    return(0);

}



/*

 * Compute an ID for a vhost based on what makes it selected by requests.

 * The second and more Host(s)/IP(s):port(s), and the ServerAlias(es) are

 * optional (see make_servers_ids() below).

 */

 static const char *make_server_id(server_rec *s, apr_pool_t *p, int full)

{

    apr_md5_ctx_t md5_ctx;

    unsigned char md5[APR_MD5_DIGESTSIZE];

    char host_ip[64]; /* for any IPv[46] string */

    server_addr_rec *sar;

    int i;



    apr_md5_init(&md5_ctx);

    for (sar = s->addrs; sar; sar = sar->next) {

        host_ip[0] = '\0';

        apr_sockaddr_ip_getbuf(host_ip, sizeof host_ip, sar->host_addr);

        apr_md5_update(&md5_ctx, (void *)sar->virthost, strlen(sar->virthost));

        apr_md5_update(&md5_ctx, (void *)host_ip, strlen(host_ip));

        apr_md5_update(&md5_ctx, (void *)&sar->host_port,

                       sizeof(sar->host_port));

        if (!full) {

            break;

        }

    }

    if (s->server_hostname) {

        apr_md5_update(&md5_ctx, (void *)s->server_hostname,

                       strlen(s->server_hostname));

    }

    if (full) {

        if (s->names) {

            for (i = 0; i < s->names->nelts; ++i) {

                const char *name = APR_ARRAY_IDX(s->names, i, char *);

                apr_md5_update(&md5_ctx, (void *)name, strlen(name));

            }

        }

        if (s->wild_names) {

            for (i = 0; i < s->wild_names->nelts; ++i) {

                const char *name = APR_ARRAY_IDX(s->wild_names, i, char *);

                apr_md5_update(&md5_ctx, (void *)name, strlen(name));

            }

        }

    }

    apr_md5_final(md5, &md5_ctx);



    return apr_pescape_hex(p, md5, sizeof md5, 0);

}



/*

 * First try to compute an unique ID for each vhost with minimal criteria,

 * that is the first Host/IP:port and ServerName. For most cases this should

 * be enough and avoids changing the ID unnecessarily accross restart (or

 * stop/start w.r.t. persisted files) for things that this module does not

 * care about.

 *

 * But if it's not enough (collisions) do a second pass for the full monty,

 * that is additionally the other Host(s)/IP(s):port(s) and ServerAlias(es).

 *

 * Finally, for pathological configs where this is still not enough, let's

 * append a counter to duplicates, because we really want that ID to be unique

 * even if the vhost will never be selected to handle requests at run time, at

 * load time a duplicate may steal the original slotmems (depending on its

 * balancers' configurations), see how mod_slotmem_shm reuses slots/files based

 * solely on this ID and resets them if the sizes don't match.

 */

static apr_array_header_t *make_servers_ids(server_rec *main_s, apr_pool_t *p)

{

    server_rec *s = main_s;

    apr_array_header_t *ids = apr_array_make(p, 10, sizeof(const char *));

    apr_hash_t *dups = apr_hash_make(p);

    int idx, *dup, full_monty = 0;

    const char *id;



    for (idx = 0, s = main_s; s; s = s->next, ++idx) {

        id = make_server_id(s, p, 0);

        dup = apr_hash_get(dups, id, APR_HASH_KEY_STRING);

        apr_hash_set(dups, id, APR_HASH_KEY_STRING,

                     apr_pmemdup(p, &idx, sizeof(int)));

        if (dup) {

            full_monty = 1;

            APR_ARRAY_IDX(ids, *dup, const char *) = NULL;

            APR_ARRAY_PUSH(ids, const char *) = NULL;

        }

        else {

            APR_ARRAY_PUSH(ids, const char *) = id;

        }

    }

    if (full_monty) {

        apr_hash_clear(dups);

        for (idx = 0, s = main_s; s; s = s->next, ++idx) {

            id = APR_ARRAY_IDX(ids, idx, const char *);

            if (id) {

                /* Preserve non-duplicates */

                continue;

            }

            id = make_server_id(s, p, 1);

            if (apr_hash_get(dups, id, APR_HASH_KEY_STRING)) {

                id = apr_psprintf(p, "%s_%x", id, idx);

            }

            else {

                apr_hash_set(dups, id, APR_HASH_KEY_STRING, (void *)-1);

            }

            APR_ARRAY_IDX(ids, idx, const char *) = id;

        }

    }



    return ids;

}



/* post_config hook: */

static int balancer_post_config(apr_pool_t *pconf, apr_pool_t *plog,

                         apr_pool_t *ptemp, server_rec *s)
@@ -738,6 +848,8 @@ static int balancer_post_config(apr_pool_t *pconf, apr_pool_t *plog, 
    proxy_server_conf *conf;

    ap_slotmem_instance_t *new = NULL;

    apr_time_t tstamp;

    apr_array_header_t *ids;

    int idx;



    /* balancer_post_config() will be called twice during startup.  So, don't

     * set up the static data the 1st time through. */
@@ -768,14 +880,16 @@ static int balancer_post_config(apr_pool_t *pconf, apr_pool_t *plog, 
        return !OK;

    }



    ids = make_servers_ids(s, ptemp);



    tstamp = apr_time_now();

    /*

     * Go thru each Vhost and create the shared mem slotmem for

     * each balancer's workers

     */

    while (s) {

    for (idx = 0; s; ++idx) {

        int i,j;

        char *id;

        const char *id;

        proxy_balancer *balancer;

        ap_slotmem_type_t type;

        void *sconf = s->module_config;
@@ -784,14 +898,7 @@ static int balancer_post_config(apr_pool_t *pconf, apr_pool_t *plog, 
         * During create_proxy_config() we created a dummy id. Now that

         * we have identifying info, we can create the real id

         */

        id = apr_psprintf(pconf, "%s.%s.%d.%s.%s.%u.%s",

                          (s->server_scheme ? s->server_scheme : "????"),

                          (s->server_hostname ? s->server_hostname : "???"),

                          (int)s->port,

                          (s->server_admin ? s->server_admin : "??"),

                          (s->defn_name ? s->defn_name : "?"),

                          s->defn_line_number,

                          (s->error_fname ? s->error_fname : DEFAULT_ERRORLOG));

        id = APR_ARRAY_IDX(ids, idx, const char *);

        conf->id = apr_psprintf(pconf, "p%x",

                                ap_proxy_hashfunc(id, PROXY_HASHFUNC_DEFAULT));

        if (conf->bslot) {

modules/slotmem/mod_slotmem_shm.c

+258 −223

File changed.

Preview size limit exceeded, changes collapsed.